1. Field of the Invention
This invention relates generally to an apparatus and method for forming dynamoelectric machine field windings, and more particularly to an apparatus and method for forming such windings by pushing. This application is a continuation of application Ser. No. 331,992, filed Feb. 12, 1973, now abandoned.
2. Description of the Prior Art
In the past, two different types of apparatus have been employed for placing dynamoelectric machine field windings in the slots of a stator core member. In the so-called in-place or gun winder, a free end of the wire is secured and a gun is oscillated through the bore of the core member thereby withdrawing the wire from a source and placing it directly in the desired slots; since the free end of the wire is fixed, the wire is in essence wound around selected teeth which define the slots thereby placing the wire under tension. A typical gun winder is shown for example in U.S. Pat. No. 3,025,008 assigned to the Assignee of the present application.
In the so-called coil-insertion or coil-injection apparatus, prewound coils are first placed on a circular array of elongated blades, the stator core is then positioned on the blades with the blades respectively engaging the inner ends of the stator core teeth, and the coils are then pushed bodily into the stator core member slots. Such coil insertion apparatus is shown for example in U.S. Pat. Nos. 2,432,267, 3,324,536, and 3,447,225, the latter patent being assigned to the Assignee of the present application. The coils for use with such coil insertion apparatus are typically formed by securing the free end of the wire to a coil form and then winding or wrapping the wire around the coil form as the wire is withdrawn from a source, the wire again being placed in tension as it is being wound. Typical apparatus for prewinding such coils is shown for example in U.S. Pat. No. 3,575,219, also assigned to the present applicant.
The above-described prior apparatus and methods for forming and placing dynamoelectric machine field coils wind or wrap the magnet wire under tension around an element. A part of the thickness of build of insulation on magnet wire used for winding dynamoelectric machine field windings is dictated by tension and/or sliding friction to which the wire is subjected, particularly in a gun winder, rather than by electrical requirements for insulation per se. Thus, an apparatus and method for forming dynamoelectric machine field coils which does not involve the application of tension to the wire will permit use of insulation having a lesser thickness of build which in turn will permit greater slot fill.
U.S. Pat. No. 3,791,419 assigned to the assignee of the present application discloses apparatus for forming dynamoelectric machine field windings by pushing. U.S. Pat. No. 3,347,474 discloses apparatus wherein the end turns of dynamoelectric machine field windings are formed by pushing.